Vehicular driving assist system

ABSTRACT

A vehicular driving assist system includes a plurality of cameras disposed at a vehicle and an image processor that processes captured image data. With a trailer equipped with at least one trailer camera hitched to the vehicle, a display screen displays video images derived from captured image data. The system determines a reversing path for the vehicle and trailer to follow to assist the driver in backing up the trailer, and generates a graphic overlay at the display screen that indicates the determined reversing path. During the backing up maneuver of the trailer hitched to the vehicle, and responsive to determination of an object rearward of the trailer, the system (i) determines an adjusted reversing path to avoid the object and (ii) adjusts the graphic overlay to indicate the adjusted reversing path of the vehicle and trailer for the driver to follow in backing up the trailer.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent application Ser. No. 16/147,946, filed Oct. 1, 2018, now U.S. Pat. No. 10,870,449, which is a continuation of U.S. patent application Ser. No. 15/238,005, filed Aug. 16, 2016, now U.S. Pat. No. 10,086,870, which claims the filing benefits of U.S. provisional application Ser. No. 62/206,443, filed Aug. 18, 2015, which is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to a vehicle vision system for a vehicle and, more particularly, to a vehicle vision system that utilizes one or more cameras at a vehicle to assist a driver of the vehicle in maneuvering the vehicle with a trailer.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known. Examples of such known systems are described in U.S. Pat. Nos. 5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporated herein by reference in their entireties.

In some systems, when attaching a trailer to the vehicle, the driver has to enter its properties to put the trailer driving aid system into a position to properly calculate the driving aids overlays, when backing up with a trailer attached. Some more advanced systems are able to detect the trailer length and the distance of the trailer's axle to the hatch by watching the trailer's turning behavior when the vehicle and trailer are in motion using visual data processing such as described in U.S. Publication No. US-2014-0160276, which is hereby incorporated herein by reference in its entirety.

Wireless camera data transmission is known, especially BLUETOOTH® and WLAN. To attach wireless cameras onto vehicles or trailers is also known. Analog image transmission (such as NTSC) to an aftermarket display device installed in the vehicle cabin is common use. In U.S. Publication No. US-2014-0340510, which is hereby incorporated herein by reference in its entirety, the integration of a trailer attached (possibly wireless) camera to an OEM vehicle (possibly top view) vision system is described including the data transmission architecture and the visual human interface. A towing vehicle based trailer stability control is well described in U.S. Publication No. US-2014-0340510.

From German DE 102009057996 (Daimler 2009), it is known how to calibrate a trailer rear-mounted camera relative to a trailing vehicle by visual motion flow analysis via difference image data processing, resulting in a corresponding set of translation and rotation parameters.

In WO 2015/001066, a vehicle trailer back up control system with trailer cameras is disclosed that is able to determine a target route (path plan) with route corridor. Also suggested is 3D representation of the scene. It lacks on describing the according vision processing and camera calibration to do so.

SUMMARY OF THE INVENTION

The present invention provides a driver assistance system or vision system or imaging system for a vehicle that utilizes one or more cameras (preferably one or more CMOS cameras) to capture image data representative of images exterior of the vehicle, with the vehicle towing a trailer that includes one or more cameras, and with the system providing enhanced maneuvering of the vehicle and trailer, such as in a reversing direction for parking a trailer.

The present invention provides a vehicle and trailer destination or parking lot determination system having a path planning algorithm and vehicle-trailer train control within a vehicle environment processed by a scene understanding system using environmental sensors and sensor fusion algorithms. The vehicle-trailer train control system utilizes visual trailer identifying and angle detection and processing algorithms. The vehicle-trailer train path planning uses a two stage path planner having a geometric planning with consecutive optimal control minimization algorithm. The environmental scene understanding system uses classifiers for the sensor clustering and input waging with a consecutive classifier based context determination algorithm.

These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle with a vision system that incorporates cameras in accordance with the present invention;

FIG. 2 is an image of a display screen displaying images in accordance with the present invention;

FIG. 3 is a plan view of a vehicle towing a trailer; and

FIG. 4 is a plan view similar to FIG. 3, showing paths of the vehicle and trailer during a rearward turning maneuver.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vehicle vision system and/or driver assist system and/or object detection system and/or alert system operates to capture images exterior of the vehicle and may process the captured image data to display images and to detect objects at or near the vehicle and in the predicted path of the vehicle, such as to assist a driver of the vehicle in maneuvering the vehicle in a rearward direction. The vision system includes an image processor or image processing system that is operable to receive image data from one or more cameras and provide an output to a display device for displaying images representative of the captured image data. Optionally, the vision system may provide display, such as a rearview display or a top down or bird's eye or surround view display or the like.

Referring now to the drawings and the illustrative embodiments depicted therein, a vehicle 10 includes an imaging system or vision system 12 that includes at least one exterior facing imaging sensor or camera, such as a rearward facing imaging sensor or camera 14 a (and the system may optionally include multiple exterior facing imaging sensors or cameras, such as a forwardly facing camera 14 b at the front (or at the windshield) of the vehicle, and a sidewardly/rearwardly facing camera 14 c, 14 d at respective sides of the vehicle), which captures images exterior of the vehicle, with the camera having a lens for focusing images at or onto an imaging array or imaging plane or imager of the camera (FIG. 1). Optionally, a forward viewing camera may be disposed at the windshield of the vehicle and view through the windshield and forward of the vehicle, such as for a machine vision system (such as for traffic sign recognition, headlamp control, pedestrian detection, collision avoidance, lane marker detection and/or the like). The vision system 12 includes a control or electronic control unit (ECU) or processor 18 that is operable to process image data captured by the camera or cameras and may detect objects or the like and/or provide displayed images at a display device 16 for viewing by the driver of the vehicle (although shown in FIG. 1 as being part of or incorporated in or at an interior rearview mirror assembly 20 of the vehicle, the control and/or the display device may be disposed elsewhere at or in the vehicle). The data transfer or signal communication from the camera to the ECU may comprise any suitable data or communication link, such as a vehicle network bus or the like of the equipped vehicle.

The present invention provides a driver assist system that assist the driver in backing up a trailer hooked to the rear of the towing vehicle. The system may utilize aspects of the systems described in U.S. Pat. No. 9,085,261 and/or U.S. Publication Nos. US-2015-0042808; US-2015-0042807; US-2015-0042806; US-2015-0002670; US-2014-0336876; US-2014-0160291; US-2014-0160276 and/or US-2014-0067206, and/or International Publication No. WO 2014/204794, which are hereby incorporated herein by reference in their entireties.

Under use of a trailer camera calibration algorithm similar to such as suggested in DE 102009057996, optionally utilizing methods such as described in U.S. Publication No. US-2014-0160276, one or multiple trailer mounted cameras may be calibratable to the vehicle sensor processing and vision system of the towing (ego-) vehicle's coordinate system, by processing the motion flow visual of the camera or sensor in relation to the motion flow of the vehicle sensor system. The coordinate system may be grid based or may be a vector map or a hybrid with grid maps for the near area and vector based in further distance (such as described in U.S. Publication No. US-2015-0344028, which is hereby incorporated herein by reference in its entirety). As an additional aspect of the invention, the vehicle towed trailer camera or cameras or optional other distance sensor or sensors, such as an ultrasound sensor or ultrasound array sensor, RADAR, Time-of-Flight (TOF) or LIDAR or the like, may be fused to the vehicle environmental map system as additional sensor input fused by the (Baysien, Adaboost or other type) classifier in the same manner as the comparable other sensor inputs to the ‘Environment and Object map’ of the sensor fusion, such as by utilizing aspects of the systems described in U.S. Publication No. US-2015-0344028. Also similar to U.S. Publication No. US-2015-0344028, the sensor(s) may have a n−1 feedback loop piping in one preceding frame or sensor sample of that same sensor and may have a static input describing the specific sensor properties (at the given point of time n) to the classifier.

In accordance with an aspect of the present invention, although areas which are (still) not encompassed by any camera as in the above cited U.S. Publication No. US-2014-0340510 may not be showable on a real time top view generated image, the mapping distance between the trailer camera (or cameras) image(s) and the images captured by the vehicle cameras may be a plausible distance when using a calibrated trailer camera. The mapping may occur in a machine vision system while the human interface may be a top scene view with the ego vehicle and the trailer in it (such as shown in FIGS. 3 and 4). FIG. 3 shows the detected environmental scene with the vehicle overlay 30 of the vehicle and the trailer overlay 31 in it. FIG. 4 shows additionally an overlay of an area inserted to the real time image by historical data (non-real time) content 32, since it is not captured by any sensor or camera. Overlays of a planned vehicle reversing path 34 and the trailer's reversing path 33 are inserted as well. The trailer and the vehicle may be overlays (augmented) having a true scale relative to the augmented vehicle and the real environmental scene, while the environmental scene may be generated non augmented from camera data and optionally other vehicle sensor's data (as discussed as optional under use of the ‘Environment and Object map’ generation using the sensor processing suggested in U.S. Publication No. US-2015-0344028). Optionally, the areas which are not encompassed by any of the four (or more) surround view vision cameras or trailer camera (or cameras) may be filled by a non-real time image patch out of the earlier detected scene's map system memory for being presented to the driver, such as by using aspects of the systems described in the above cited U.S. Publication No. US-2014-0160276. Optionally, that non-real time scene content (such as the scene area that is not in sensor range or that has a too low confidence level (such as, for example, areas in range of RGB cameras which are in darkness or, for example, ultrasound sensors in front of grass in the sensor range that is waving in the wind)) may be highlighted in any suitable manner, such as partially darkening, applying a blinking or colored overlay or by having blinking boundaries, since the non-real time space may be good for assuming the drivable (static) space but may lead a driver to overlook dynamic scene components such as a person or vehicle which may have stepped or drove into that maneuvering area which may be hazardous for that person, such as can be understood with reference to FIG. 4.

In the customer interface described in U.S. Publication No. US-2014-0340510, and such as shown in FIG. 2 (which corresponds to FIG. 40 of U.S. Publication No. US-2014-0340510), it desirable to have some area between the vehicle rear camera and the trailer camera within the top view image showing voids or black bars in the top view image display mode (with vehicle plus trailer) between the areas encompassed by the vehicle cameras and the area encompassed by the trailer camera since the trailer camera was not calibratable with the vehicle cameras.

Optionally, automated trailer parking or ramp docking DAS may be realized by using an optimal control algorithm under use of a cost minimization function, optionally having a two stage path planner having a first planning stage with a geometrical constructed path planning and a consecutive stage running an optimal control minimization algorithm, which is for smoothing the path and reducing set point extreme values, similar to that suggested in U.S. patent application Ser. No. 15/206,801, filed Jul. 11, 2016 and published Jan. 19, 2017 as U.S. Publication No. US-2017-0015312, and/or U.S. Publication No. US-2015-0344028, which are hereby incorporated herein by reference in their entireties. Known trailer assistant systems allow the user to navigate a trailer (that is hooked on a propelling or driven vehicle) rearwardly in a curvature controlled manner. In general, trailers behave unstably when being pushed rearwardly. Also, skilled drivers are challenged when backing up vehicle-trailer-trains. Curvature controlling trailer assist systems ease the task by controlling the vehicle's steering wheels in a manner that the trailer is describing a curve in a radius actually set by the user's input, such as described in U.S. Publication No. US-2012-0271515.

It is known that the trailer's path and/or the vehicle's path according to the actual set point is augmented on the vehicle's vision system, such as, for example, via a top view vision system. Since naturally the rear vehicle camera is mostly blocked by the trailer which is being towed by the vehicle, the path to the area the trailer is moving towards is not visible by the vehicle rear camera. To overcome this matter, some OEMs offer the solution that the vehicle vision is transferred to a smart phone and also the vehicle's curvature and longitudinal control is implemented on the smart phone. The user sets the curvature setpoint of the trailer and steers the speed of the vehicle-trailer train. Since the user can exit the vehicle and watch the scene from aside, possibly invisible to any towing vehicle camera, he or she can avoid backing the trailer into a collision or harming someone.

DE 000010128792 discloses a collision avoidance and warning system of drive trains with trailers for maneuvering forward or backwardly. In there it is disclosed that required driving space for the towing vehicle and the trailer all together gets predicted. That system's prediction does not include trajectory planning, the prediction is limited to one circle segment and is based on holding the actual trailer steering angle. The reality is different when maneuvering a trailer forwardly or rearwardly in curves for reaching a specific spot or for avoiding obstacles.

For easier prediction of the last trailer's path of multi-link trains, the curves can be planned in circle segments optionally. In DE 102008043675, a control for controlling the rearward traveling path of multiple links attached to a leading towing vehicle with just the towing vehicle's front wheels controllable was suggested. The control mathematics were more or less poor or not executable in practice since a couple of correction constants were to be determined. Nonholonomic motion path planning of n-trailers by using the Gourset normal form was discussed in IEEE Transactions on Automatik Control, Vol. 40, No. 5, May 1995. Another approach capable to avoid dynamic obstacles was shown by Lamiraux in Springer Path Optimization for Nonholonomic Systems: Application to Reactive Obstacle Avoidance and Path Planning, 2003.

The vehicle-trailer train path planner of the present invention may utilize one of the path planning strategies as described in the above cited references or one similar to the planner and control recently published in International Publication No. WO 2015/001066. International Publication No. WO 2015/001066 though may lack executability by a person skilled in the subject since it does not include any disclosure on how to calibrate the trailer cameras or sensors to the vehicle system so that the control can steer the trailer along a designated path automatically. Without calibration, the scene detection may fail, the path planning, which is depending on a correct scene detection, may fail and the maneuver execution may fail because the path will not match to the real scene, although the path planner itself may work correctly (but using wrong input data).

Departing from the prior art, including International Publication No. WO 2015/001066, the system of the present invention uses the trailer camera not just to determine that the trailer is approaching possibly hazardous objects but to assimilate the visual scene information to the vehicle's scene sensor processing (master-) system. The trailer cameras are calibrated essentially by motion flow (such as to correct for improper installation, such as being tilted, rolled or yawed or being off center), such as similar to the calibration of the surround vision system's fish eye cameras (14 a, 14 b, 14 c and 14 d) attached to the (towing) vehicle such as shown in FIG. 1. The calibration may require the vehicle-trailer train to be in motion, for having motion flow. The scenery may require some texture or pattern so that the system has some fix points to track and motion assess. The texture or pattern should be naturally given when the train is driven in natural environment (such as given by trees, buildings, vehicles, and/or the like in the environment surrounding the vehicle and trailer). The initial test drive for initializing the trailer camera in coordinates to the tow vehicle born coordinate (map-) system may be comparably short, such as about 10 m or thereabouts. The additionally required trailer angle detection system may be (towing-) vehicle rear camera based or vehicle rear end ultrasound sensor (possibly ultrasound sensor array) based or may be another direct mounted angle sensor based or contactless sensor based system capable of detecting the trailer angle against the towing vehicle, optionally having a dedicated target (sticker) on the trailer to enable the trailer angle detection system to function, or optionally targetless trailer detection may be incorporated in the automated trailer path control system of the present invention.

Optionally, the trailer path control system of the present invention may additionally be capable of avoiding hazards with dynamic objects such as pedestrians walking through the pursued trailer destination or parking spot or the path to it. The system's algorithm may have a threshold time which alters the classification of a moving object to a static object when it comes to a stop over a certain time (such as, for example, when another vehicle within the environmental scene [map] stops). While the system may just wait until a moving object, such as, for example, a pedestrian or the like, has left the trailer train destination path, the system may optionally redo the path planning in case the static map has changed, such as when another vehicle has occupied (and stopped) a part of the free space that was part of the destination path originally.

The system may utilize aspects of the trailering or trailer angle detection systems described in U.S. Pat. Nos. 9,086,261 and/or 6,690,268, and/or U.S. Publication Nos. US-2015-0217693; US-2014-0160276; US-2014-0085472 and/or US-2015-0002670, and/or U.S. provisional applications, Ser. No. 62/303,546, filed Mar. 4, 2016, and/or Ser. No. 62/290,167, filed Feb. 2, 2016, which are hereby incorporated herein by reference in their entireties.

The camera or sensor may comprise any suitable camera or sensor. Optionally, the camera may comprise a “smart camera” that includes the imaging sensor array and associated circuitry and image processing circuitry and electrical connectors and the like as part of a camera module, such as by utilizing aspects of the vision systems described in International Publication Nos. WO 2013/081984 and/or WO 2013/081985, which are hereby incorporated herein by reference in their entireties.

The system includes an image processor operable to process image data captured by the camera or cameras, such as for detecting objects or other vehicles or pedestrians or the like in the field of view of one or more of the cameras. For example, the image processor may comprise an image processing chip selected from the EYEQ family of image processing chips available from Mobileye Vision Technologies Ltd. of Jerusalem, Israel, and may include object detection software (such as the types described in U.S. Pat. Nos. 7,855,755; 7,720,580 and/or 7,038,577, which are hereby incorporated herein by reference in their entireties), and may analyze image data to detect vehicles and/or other objects. Responsive to such image processing, and when an object or other vehicle is detected, the system may generate an alert to the driver of the vehicle and/or may generate an overlay at the displayed image to highlight or enhance display of the detected object or vehicle, in order to enhance the driver's awareness of the detected object or vehicle or hazardous condition during a driving maneuver of the equipped vehicle.

The vehicle may include any type of sensor or sensors, such as imaging sensors or radar sensors or lidar sensors or ladar sensors or ultrasonic sensors or the like. The imaging sensor or camera may capture image data for image processing and may comprise any suitable camera or sensing device, such as, for example, a two dimensional array of a plurality of photosensor elements arranged in at least 640 columns and 480 rows (at least a 640×480 imaging array, such as a megapixel imaging array or the like), with a respective lens focusing images onto respective portions of the array. The photosensor array may comprise a plurality of photosensor elements arranged in a photosensor array having rows and columns. Preferably, the imaging array has at least 300,000 photosensor elements or pixels, more preferably at least 500,000 photosensor elements or pixels and more preferably at least 1 million photosensor elements or pixels. The imaging array may capture color image data, such as via spectral filtering at the array, such as via an RGB (red, green and blue) filter or via a red/red complement filter or such as via an RCC (red, clear, clear) filter or the like. The logic and control circuit of the imaging sensor may function in any known manner, and the image processing and algorithmic processing may comprise any suitable means for processing the images and/or image data.

For example, the vision system and/or processing and/or camera and/or circuitry may utilize aspects described in U.S. Pat. Nos. 9,233,641; 9,146,898; 9,174,574; 9,090,234; 9,077,098; 8,818,042; 8,886,401; 9,077,962; 9,068,390; 9,140,789; 9,092,986; 9,205,776; 8,917,169; 8,694,224; 7,005,974; 5,760,962; 5,877,897; 5,796,094; 5,949,331; 6,222,447; 6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202; 6,201,642; 6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452; 6,822,563; 6,891,563; 6,946,978; 7,859,565; 5,550,677; 5,670,935; 6,636,258; 7,145,519; 7,161,616; 7,230,640; 7,248,283; 7,295,229; 7,301,466; 7,592,928; 7,881,496; 7,720,580; 7,038,577; 6,882,287; 5,929,786 and/or 5,786,772, and/or U.S. Publication Nos. 2014/0340510; 2014/0313339; 2014/0347486; 2014/0320658; 2014/0336876; 2014/0307095; 2014/0327774; 2014/0327772; 2014/0320636; 2014/0293057; 2014/0309884; 2014/0226012; 2014/0293042; 2014/0218535; 2014/0218535; 2014/0247354; 2014/0247355; 2014/0247352; 2014/0232869; 2014/0211009; 2014/0160276; 2014/0168437; 2014/0168415; 2014/0160291; 2014/0152825; 2014/0139676; 2014/0138140; 2014/0104426; 2014/0098229; 2014/0085472; 2014/0067206; 2014/0049646; 2014/0052340; 2014/0025240; 2014/0028852; 2014/005907; 2013/0314503; 2013/0298866; 2013/0222593; 2013/0300869; 2013/0278769; 2013/0258077; 2013/0258077; 2013/0242099; 2013/0215271; 2013/0141578 and/or 2013/0002873, which are all hereby incorporated herein by reference in their entireties. The system may communicate with other communication systems via any suitable means, such as by utilizing aspects of the systems described in International Publication Nos. WO 2010/144900; WO 2013/043661 and/or WO 2013/081985, and/or U.S. Pat. No. 9,126,525, which are hereby incorporated herein by reference in their entireties.

The imaging device and control and image processor and any associated illumination source, if applicable, may comprise any suitable components, and may utilize aspects of the cameras (such as various imaging sensors or imaging array sensors or cameras or the like, such as a CMOS imaging array sensor, a CCD sensor or other sensors or the like) and vision systems described in U.S. Pat. Nos. 5,760,962; 5,715,093; 6,922,292; 6,757,109; 6,717,610; 6,590,719; 6,201,642; 5,796,094; 6,559,435; 6,831,261; 6,822,563; 6,946,978; 7,720,580; 8,542,451; 7,965,336; 7,480,149; 5,550,677; 5,877,897; 6,498,620; 5,670,935; 5,796,094; 6,396,397; 6,806,452; 6,690,268; 7,005,974; 7,937,667; 7,123,168; 7,004,606; 6,946,978; 7,038,577; 6,353,392; 6,320,176; 6,313,454 and/or 6,824,281, and/or International Publication Nos. WO 2009/036176; WO 2009/046268; WO 2010/099416; WO 2011/028686 and/or WO 2013/016409, and/or U.S. Pat. Publication Nos. US 2010-0020170 and/or US-2009-0244361, which are all hereby incorporated herein by reference in their entireties.

Optionally, the vision system may include a display for displaying images captured by one or more of the imaging sensors for viewing by the driver of the vehicle while the driver is normally operating the vehicle. Optionally, for example, the vision system may include a video display device disposed at or in the interior rearview mirror assembly of the vehicle, such as by utilizing aspects of the video mirror display systems described in U.S. Pat. No. 6,690,268 and/or U.S. Publication No. US-2012-0162427, which are hereby incorporated herein by reference in their entireties. The video mirror display may comprise any suitable devices and systems and optionally may utilize aspects of the compass display systems described in U.S. Pat. Nos. 7,370,983; 7,329,013; 7,308,341; 7,289,037; 7,249,860; 7,004,593; 4,546,551; 5,699,044; 4,953,305; 5,576,687; 5,632,092; 5,677,851; 5,708,410; 5,737,226; 5,802,727; 5,878,370; 6,087,953; 6,173,508; 6,222,460; 6,513,252 and/or 6,642,851, and/or European patent application, published Oct. 11, 2000 under Publication No. EP 0 1043566, and/or U.S. Publication No. US-2006-0061008, which are all hereby incorporated herein by reference in their entireties. Optionally, the video mirror display screen or device may be operable to display images captured by a rearward viewing camera of the vehicle during a reversing maneuver of the vehicle (such as responsive to the vehicle gear actuator being placed in a reverse gear position or the like) to assist the driver in backing up the vehicle, and optionally may be operable to display the compass heading or directional heading character or icon when the vehicle is not undertaking a reversing maneuver, such as when the vehicle is being driven in a forward direction along a road (such as by utilizing aspects of the display system described in International Publication No. WO 2012/051500, which is hereby incorporated herein by reference in its entirety).

Optionally, the vision system (utilizing the forward facing camera and a rearward facing camera and other cameras disposed at the vehicle with exterior fields of view) may be part of or may provide a display of a top-down view or birds-eye view system of the vehicle or a surround view at the vehicle, such as by utilizing aspects of the vision systems described in International Publication Nos. WO 2010/099416; WO 2011/028686; WO 2012/075250; WO 2013/019795; WO 2012/075250; WO 2012/145822; WO 2013/086249 and/or WO 2013/109869, and/or U.S. Publication No. US-2012-0162427, which are hereby incorporated herein by reference in their entireties.

Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the invention, which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents. 

1. A vehicular driving assist system, said vehicular driving assist system comprising: a plurality of vehicle cameras disposed at a vehicle and having respective fields of view exterior of the vehicle, wherein said plurality of vehicle cameras includes a rear backup camera disposed at a rear portion of the vehicle and viewing at least rearward of the vehicle; at least one trailer camera disposed at a trailer hitched to the vehicle and having a respective field of view exterior of the trailer; an image processor operable to process image data captured by said plurality of vehicle cameras and by said at least one trailer camera; wherein, responsive to processing of image data captured by said plurality of vehicle cameras and by said at least one trailer camera during a backing up maneuver of the trailer hitched to the vehicle, said vehicular driving assist system determines objects rearward of the trailer that are present in the field of view of said at least one trailer camera; a display screen disposed in the vehicle for viewing by a driver of the vehicle, wherein said display screen displays video images derived from image data captured by at least one camera selected from the group consisting of (i) said plurality of vehicle cameras and (ii) said at least one trailer camera; wherein said vehicular driving assist system determines a reversing path for the vehicle and trailer to follow to assist the driver in backing up the trailer; wherein said vehicular driving assist system generates a graphic overlay at said display screen overlaying the displayed video images, the graphic overlay indicating the determined reversing path for the driver to follow in backing up the trailer; and wherein, during the backing up maneuver of the trailer hitched to the vehicle along the determined reversing path, and responsive to determination of an object rearward of the trailer via processing of image data captured by at least said at least one trailer camera, said vehicular driving assist system (i) determines an adjusted reversing path to avoid the object and (ii) adjusts the graphic overlay to indicate the adjusted reversing path of the vehicle and trailer for the driver to follow in backing up the trailer.
 2. The vehicular driving assist system of claim 1, wherein said vehicular driving assist system controls a steering system of the vehicle to steer the vehicle to back up the trailer along the determined reversing path.
 3. The vehicular driving assist system of claim 1, wherein, responsive to processing of image data captured by said plurality of vehicle cameras and by said at least one trailer camera while the vehicle is backing up the trailer, said vehicular driving assist system initializes said at least one trailer camera in coordinates that correspond to coordinates of said plurality of vehicle cameras.
 4. The vehicular driving assist system of claim 1, wherein said vehicular driving assist system calibrates said at least one trailer camera responsive at least in part to a determination of a trailer angle of a longitudinal axis of the trailer relative to a longitudinal axis of the vehicle.
 5. The vehicular driving assist system of claim 4, wherein said vehicular driving assist system determines the trailer angle responsive at least in part to image processing of image data captured by at least said rear backup camera of said plurality of vehicle cameras.
 6. The vehicular driving assist system of claim 4, wherein said vehicular driving assist system determines the trailer angle responsive at least in part to image processing of image data captured by at least said rear backup camera of said plurality of vehicle cameras and image data captured by said at least one trailer camera.
 7. The vehicular driving assist system of claim 1, wherein the at least one trailer camera at least comprises a rearward viewing trailer camera viewing at least rearward of the trailer.
 8. The vehicular driving assist system of claim 1, wherein, responsive to the determination of the object rearward of the trailer, said vehicular driving assist system generates an alert to alert the driver of the vehicle.
 9. The vehicular driving assist system of claim 1, wherein, responsive to determination of an object rearward of the trailer, said vehicular driving assist system controls a braking system of the vehicle.
 10. The vehicular driving assist system of claim 1, wherein, responsive to determination of an object rearward of the trailer, said vehicular driving assist system controls a steering system of the vehicle.
 11. The vehicular driving assist system of claim 1, wherein said vehicular driving assist system utilizes a trailer identifying and angle detection algorithm.
 12. The vehicular driving assist system of claim 1, wherein said vehicular driving assist system determines the reversing path using a two stage path planner.
 13. The vehicular driving assist system of claim 12, wherein the two stage path planner comprises a geometric planning with consecutive optimal control minimization algorithm.
 14. A vehicular driving assist system, said vehicular driving assist system comprising: a plurality of vehicle cameras disposed at a vehicle and having respective fields of view exterior of the vehicle, wherein said plurality of vehicle cameras includes a rear backup camera disposed at a rear portion of the vehicle and viewing at least rearward of the vehicle; a rearward viewing trailer camera disposed at a rear portion of a trailer hitched to the vehicle, said rearward viewing trailer camera viewing at least rearward of the trailer; an image processor operable to process image data captured by said plurality of vehicle cameras and by said rearward viewing trailer camera; wherein, responsive to processing of image data captured by said plurality of vehicle cameras and by said rearward viewing trailer camera during a backing up maneuver of the trailer hitched to the vehicle, said vehicular driving assist system determines objects rearward of the trailer that are present in the field of view of said rearward viewing trailer camera; a display screen disposed in the vehicle for viewing by a driver of the vehicle, wherein said display screen displays video images derived from image data captured by at least one camera selected from the group consisting of (i) said plurality of vehicle cameras and (ii) said rearward viewing trailer camera; wherein said vehicular driving assist system determines a reversing path for the vehicle and trailer to follow to assist the driver in backing up the trailer; wherein said vehicular driving assist system generates a graphic overlay at said display screen overlaying the displayed video images, the graphic overlay indicating the determined reversing path; wherein said vehicular driving assist system controls a steering system of the vehicle to steer the vehicle to back up the trailer along the determined reversing path; and wherein, during the backing up maneuver of the trailer hitched to the vehicle along the determined reversing path, and responsive to determination of an object rearward of the trailer via processing of image data captured by at least said rearward viewing trailer camera, said vehicular driving assist system (i) determines an adjusted reversing path to avoid the object, (ii) adjusts the graphic overlay to indicate the adjusted reversing path of the vehicle and trailer and (iii) controls the steering system of the vehicle to steer the vehicle to back up the trailer along the adjusted reversing path.
 15. The vehicular driving assist system of claim 14, wherein, responsive to processing of image data captured by said plurality of vehicle cameras and by said rearward viewing trailer camera while the vehicle is backing up the trailer, said vehicular driving assist system initializes said rearward viewing trailer camera in coordinates that correspond to coordinates of said plurality of vehicle cameras.
 16. The vehicular driving assist system of claim 14, wherein, responsive to the determination of the object rearward of the trailer, said vehicular driving assist system generates an alert to alert the driver of the vehicle.
 17. The vehicular driving assist system of claim 14, wherein, responsive to determination of an object rearward of the trailer, said vehicular driving assist system controls a braking system of the vehicle.
 18. A vehicular driving assist system, said vehicular driving assist system comprising: a plurality of vehicle cameras disposed at a vehicle and having respective fields of view exterior of the vehicle, wherein said plurality of vehicle cameras includes a rear backup camera disposed at a rear portion of the vehicle and viewing at least rearward of the vehicle; a rearward viewing trailer camera disposed at a rear portion of a trailer hitched to the vehicle, said rearward viewing trailer camera viewing at least rearward of the trailer; an image processor operable to process image data captured by said plurality of vehicle cameras and by said rearward viewing trailer camera; wherein, responsive to processing of image data captured by said plurality of vehicle cameras and by said rearward viewing trailer camera during a backing up maneuver of the trailer hitched to the vehicle, said vehicular driving assist system determines objects rearward of the trailer that are present in the field of view of said rearward viewing trailer camera; wherein said vehicular driving assist system calibrates said rearward viewing trailer camera responsive at least in part to a determination of a trailer angle of a longitudinal axis of the trailer relative to a longitudinal axis of the vehicle; a display screen disposed in the vehicle for viewing by a driver of the vehicle, wherein said display screen displays video images derived from image data captured by at least one camera selected from the group consisting of (i) said plurality of vehicle cameras and (ii) said rearward viewing trailer camera; wherein said vehicular driving assist system determines a reversing path for the vehicle and trailer to follow to assist the driver in backing up the trailer; wherein said vehicular driving assist system generates a graphic overlay at said display screen overlaying the displayed video images, the graphic overlay indicating the determined reversing path for the driver to follow in backing up the trailer; and wherein, during the backing up maneuver of the trailer hitched to the vehicle along the determined reversing path, and responsive to determination of an object rearward of the trailer via processing of image data captured by at least said rearward viewing trailer camera, said vehicular driving assist system (i) determines an adjusted reversing path to avoid the object and (ii) adjusts the graphic overlay to indicate the adjusted reversing path for the driver to follow in backing up the trailer.
 19. The vehicular driving assist system of claim 18, wherein said vehicular driving assist system controls a steering system of the vehicle to steer the vehicle to back up the trailer along the determined reversing path.
 20. The vehicular driving assist system of claim 18, wherein said vehicular driving assist system determines the trailer angle responsive at least in part to image processing of image data captured by at least said rear backup camera of said plurality of vehicle cameras.
 21. The vehicular driving assist system of claim 18, wherein said vehicular driving assist system determines the trailer angle responsive at least in part to image processing of image data captured by at least said rear backup camera of said plurality of vehicle cameras and image data captured by said rearward viewing trailer camera.
 22. The vehicular driving assist system of claim 18, wherein, responsive to the determination of the object rearward of the trailer, said vehicular driving assist system generates an alert to alert the driver of the vehicle.
 23. The vehicular driving assist system of claim 18, wherein, responsive to determination of an object rearward of the trailer, said vehicular driving assist system controls a braking system of the vehicle. 